Another experiment - Circular channels without dielectric plate


Emmett Browns Ghost
Jun 29, 2009
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My Satellite Setup
IP9000HD +
TD110 Dish and TD88 Dish in Tandem
66°East to 60°West.
AZbox PrmHD + OpnbxS9HD + Skybox + DrHD F15
2x VboxII AZ-EL
2 m+ Alcoa PF + BSC421 C-Band lnbf...
+SS2/TwHnS2-3200 pci/TBS6925 pci
1.5 Fortec Star -Gbox - HtoH Ku/Ka/C
My Location
Hi friends ..
The rain finally made it to Manchester as expected it seemed a good time to try this ..
The object make a list of all circular polarised transponders which can be locked solid without inserting any kind of depolarising dielectric plate ..
I've tried it the other way round ..linear polarised channels with a plate figured it worth a go.
It in theory should highlight those channels less critical to depolarisation ..though obviously dish size is still relevant.
There were many transponders producing signal in excess of 6db (F15 readings) ..which would normally be enough for lock ..but if a channel on the same or adjacent frequency is using the opposite polarisation left or right circular ..then obviously the receiver would be confused as to which to lock to ..thus lock.
So waffle over is that list..
From 20 East to 40 West.

Arabsat 5C at 20.0°E
TV Oromiyaa 3707 R 10.4 db
SSTV2 3712 R 6.5 db
ETV mux 3863 L 5.4 db
Arabsat mux 3885 R 5.7db
TV de Mauritanie 3913 R 9.7db
Arabsat/ASBU Bouquet 3935 L 6.5db
Qatari mux 4055L 7.4 db

Rascom QAF 1R at 2.8°E
Congo-Kinshasa mux 4052 R 6.0db

Intelsat 10-02 at 1.0°W
BBC Arabic 4025 R 6.0db

Eutelsat 5 West A at 5.0°W
(RFO feeds) 3630 R 4.9db
Tele Congo 3633 R 9.1db
STV 3638 R 6.9db
ETV (Ethiopia) 3641 R 8.6db
Télé Sahel 3646 R 7.4db
Télé Africa 4114 L 7.3db

Express AM44 at 11.0°W
Perviy kanal 3662 R 6.3db

Express A4 at 14.0°W
Russian mux 3625 R 7.8 db

SES 4 at 22.0°W
American Forces Network (encrypted) 4115 L 9.9db

Intelsat 905 at 24.5°W
ERTU mux 3686 R 9.2db

Intelsat 907 at 27.5°W
VoA TV 3719 R 6.9db
RTP Internacional 3839 R 6.5db
Record Europa 4049 R 7.6db
NTA International 4143 R 8.1 db

NSS 806 at 40.5°W
ERT World 3630 L 5.2 db
CNB TV 3641 R 6.0db
Cosmovision 3964 R 9.5db
Telemedellin 3966 R 10.7db
Hipodrom San Isdoro 4059 R 5.8 db
JBN TV 4142 L 7.3 db
Rede Gospel 4151 R 5.8 db
NET TV 4125 L 5.9 db

Intelsat 707 at 53.0°W
Africable 3740 R >>>>> very occasional lock at 2db

hope this table is of some use ..and would appreciate if any of our Cbanders could verify and possibly list lockable signals without depolarisation their convenience of course ..
No rush ..its purely academic.


Oct 5, 2009
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My Satellite Setup
C-band: CM 240cm PF 34W-50W linear Avcomm feedring & OMT + 2x Astrotel Precision LNB & circular Avcomm polarizer + Zinwell LNBF, IRTE 180 cm 1W-34W + ESX241. DM820HD, VU+ Zero, DM500HDv2, Cisco D9865 AFN, TBS 5925 & 6983, XFinder
My Location
works also pretty good at 47.5W where I get better signal with my main linear LNB than with circular LNB which is 6-7 degrees off center
4055 locks with up to 11 db, nasa 4k 4177 transponder usually locks at 7dB on my 2.4m dish, while there's no lock on either of these TPs with the circular LNB